Name Maeike Zijlmans
Department of Neurology and Neurosurgery
Section Brain Function and Plasticity
Function PhD-student, MD
E-mail:
g.j.m.zijlmans@umcutrecht.nl Supervisors dr GJM Huiskamp, dr FSS Leijten, prof dr AC van Huffelen and prof J Gotman from the Montreal Neurological Institute.
Title research
presurgical source localization in epilepsy
Summary research
About 20% of all focal epilepsies are resistant to medical treatment. Through resection of a well-defined epileptic source, seizure freedom can be achieved. The most important presurgical diagnostic techniques are EEG (electro-encephalogram) and MRI. EEG can measure rhythmic (ictal) activity during seizures and discharges in between seizures (interictal epileptiform discharges). Inability to localize a source is the main reason for rejection for epilepsy surgery. Accurate localization of EEG-activity is difficult because this is based on mathematical models with assumptions. Novel non-invasive techniques
like magneto-encephalogram (MEG) and EEG-correlated functional MRI (EEG-fMRI) are less hindered by the problems EEG encounters and can improve localization. However, both techniques encounter problems in the identification of relevant activity. The gold standard for the localization of epileptiform activity is the electrocorticogram (ECoG), which is the EEG measured directly from the cortex. This technique is invasive and long-term ECoG is only performed in difficult cases. Recently a new kind of
activity has been discovered in ECoG, so called high-frequency oscillations (HFOs), which can only be seen in ECoG when recorded with a high sampling rate and with smaller electrodes, as used in the Montreal Neurological Institute. Interictal HFOs are more specific for the seizure onset zone than other interictal epileptiform discharges and could reveal the patho(electro-)physiology of epilepogenesis. Knowledge derived from HFOs possibly enables solving problems encountered by the non-invasive techniques MEG and EEG-fMRI.
After Maeike Zijlmans studied the value of EEG, MEG and EEG-fMRI in epileptic source localization, she went to the Montreal Neurological Institute to study high frequency oscillations in intracranial EEG. Finally, she wants to implement this technique in Utrecht and compare high frequency oscillations to non-invasive source localization in close collaboration with the MNI. For this project she received an AGIKO-grant from the Netherlands Organization for Scientific Research (NWO) and financial support from the University Medical Centre (Internationalization Program).
International collaboration:prof Jean Gotman, Montreal Neurological Institute, McGill University
Publications Zijlmans M, Buskens E, Hersevoort M, Huiskamp G, van Huffelen AC, Leijten FS.
Should we reconsider epilepsy surgery? The motivation of patients once rejected.
Seizure. Epub 2007 Dec 3.
Zijlmans M, Huiskamp G, Hersevoort M, Seppenwoolde JH, van Huffelen AC, Leijten FS. EEG-fMRI in the preoperative work-up for epilepsy surgery. Brain. 2007;130:2343-53.
Zijlmans GJ, Huijbregts JE, van Nielen KM. [Fracture of the femoral neck in bed caused by an epileptic seizure] Ned Tijdschr Geneeskd 2006;150:747-9. Dutch.
Zijlmans M, Huiskamp GM, Leijten FS, Van Der Meij WM, Wieneke G, Van Huffelen AC. Modality-specific spike identification in simultaneous magnetoencephalography/electroencephalography: a methodological approach.
J Clin Neurophysiol 2002;19:183-91.
Zijlmans M, Flanagan D, Gotman J. Heart rate changes and ECG abnormalities during epileptic seizures: prevalence and definition of an objective clinical sign. Epilepsia 2002;43:847-54.